Search results for: material strength

Authors: P. Deepak Kumar, P. R. Maiti

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In recent years, sediment scour near bridge piers and abutment is a serious problem which causes nationwide concern because it has resulted in more bridge failures than other causes. Scour is the formation of scour hole around the structure mounted on and embedded in erodible channel bed due to the erosion of soil by flowing water. The formation of scour hole around the structures depends upon shape and size of the pier, depth of flow as well as angle of attack of flow and sediment characteristics. The flow characteristics around these structures change due to man-made obstruction in the natural flow path which changes the kinetic energy of the flow around these structures. Excessive scour affects the stability of the foundation of the structure by the removal of the bed material. The accurate estimation of scour depth around bridge pier is very difficult. The foundation of bridge piers have to be taken deeper and to provide sufficient anchorage length required for stability of the foundation. In this study, computational model simulations using a 3D Computational Fluid Dynamics (CFD) model were conducted to examine the mechanism of scour around a cylindrical pier. Subsequently, the flow characteristics around these structures are presented for different flow conditions. Mechanism of scouring phenomenon, the formation of vortex and its consequent effect is discussed for a straight channel. Effort was made towards estimation of scour depth around bridge piers under different flow conditions.

Keywords: bridge pier, computational fluid dynamics, multigrid, pier shape, scour

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Authors: Taleb L., Benarbia M., Brahmi M., Belmiloud H., Boukerche A.

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Introduction and purpose of the study: Cavum cancer in children and adolescents is rare and represents 8% of all nasopharyngeal cancers treated in our department. Our objective is to study its epidemiological, clinical, therapeutic, and evolutionary particularities. Material and methods: Retrospective study of 39 patients under 20 years old, treated for undifferentiated non-metastatic carcinoma of the nasopharynx at the Emir Abdelkader Cancer Center between 2014 and 2020. Results and statistical analysis: Median age was 14 years [7-19 years], with a sex ratio of 2.9. The median time to diagnosis was 5.6 months [1 to 14 months], the circumstances of the discovery of which were dominated by lymph node syndrome in 43.6% of cases (n=17) followed by a rhinological syndrome in 30.8% of cases (n=13). The tumor stage was T1 for two patients (5.1%), T2 for 8 (20.5%), T3 for 9 (23.1%), T4 for 20 (51.3%), N0 for 2 (5 .1%) N1 for 4 (10.3%), N2 for 28 (71.8%) and N3 for 5 (12.8%). All patients received induction chemotherapy followed by concomitant radiotherapy with cisplatin. The dose of irradiation delivered to the cavum and adenopathies was 66 Gy with fractionation of 2 Gy per session in 69.2% of cases (n=27) and 1.8 Gy in 30.8% of cases (n=12). With a median follow-up of 51 months (15 to 97 months), the locoregional, metastatic, specific, and overall relapse-free survival rates at five years were 91.1%, 73.5%, 66.1%, and 68.4, respectively. Conclusion: Chemotherapy and radiotherapy treatment of cavum cancer in children and adolescents has allowed excellent locoregional control despite the advanced stage of the disease. However, the frequency of metastatic relapses could justify the possible use of systemic maintenance treatment.

Keywords: cancer, nasopharynx, radiotherapy, chemotherapy, survival

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Authors: Maryam Ghareh Chaei, Masuzyo Chilwesa, Ali Akbarnezhad, Arnaud Castel, Redmond Lloyd, Stephen Foster

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Cement hydration is an exothermic chemical reaction generally leading to a rise in concrete’s temperature. This internal heating of concrete may, in turn, lead to a temperature difference between the hotter interior and the cooler exterior of concrete and thus differential thermal stresses in early ages which could be particularly significant in mass concrete. Such differential thermal stresses result in early age thermal cracking of concrete when exceeding the concrete’s tensile strength. The extent of temperature rise and thus early age differential thermal stresses is generally a function of hydration heat intensity, thermal properties of concrete and size of the concrete element. Both hydration heat intensity and thermal properties of concrete may vary considerably with variations in the type cementitious materials and other constituents. With this in mind, partial replacement of cement with supplementary cementitious materials including fly ash and ground granulated blast furnace slag has been investigated widely as an effective strategy to moderate the heat generation rate and thus reduce the risk of early age thermal cracking of concrete. However, there is currently a lack of adequate literature on effect of partial replacement of cement with fly ash and/or ground granulated blast furnace slag on the thermal properties of concrete. This paper presents the results of an experimental conducted to evaluate the effect of addition of varying percentages of fly ash (up to 60%) and ground granulated blast furnace slag (up to 50%) on the heat capacity and thermal conductivity of early age cement paste. The water to cementitious materials ratio is kept 0.45 for all the paste samples. The results of the experimental studies were used in a numerical analysis performed using Comsol Multiphysics to highlight the effects of variations in the thermal properties of concrete, due to variations in the type of aggregate and content of supplemenraty cementitious materials, on the risk of early age cracking of a concrete raft.

Keywords: thermal diffusivity, early age thermal cracking, concrete, supplementary cementitious materials

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Authors: Xin Chen, Xinyong Li, Qidong Zhao, Dong Wang

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A new coupling system was constructed by combining photo-electrochemical cell with electro-fenton cell (PEC-EF). The electrode material in this system was derived from MnyFe₁₋yCo Prussian-Blue-Analog (PBA). Mn₀.₄Fe₀.₆Co₀.₆₇-N@C spin-coated on carbon paper behaved as the gas diffusion cathode and Mn₀.₄Fe₀.₆Co₀.₆₇O₂.₂ spin-coated on fluorine-tin oxide glass (FTO) as anode. The two separated cells could degrade Sulfamethoxazole (SMX) simultaneously and some coupling mechanisms by PEC and EF enhancing the degradation efficiency were investigated. The continuous on-site generation of H₂O₂ at cathode through an oxygen reduction reaction (ORR) was realized over rotating ring-disk electrode (RRDE). The electron transfer number (n) of the ORR with Mn₀.₄Fe₀.₆Co₀.₆₇-N@C was 2.5 in the selected potential and pH range. The photo-electrochemical properties of Mn₀.₄Fe₀.₆Co₀.₆₇O₂.₂ were systematically studied, which displayed good response towards visible light. The photoinduced electrons at anode can transfer to cathode for further use. Efficient photo-electro-catalytic performance was observed in degrading SMX. Almost 100% SMX removal was achieved in 120 min. This work not only provided a highly effective technique for antibiotic treatment but also revealed the synergic effect between PEC and EF.

Keywords: electro-fenton, photo-electrochemical, synergic effect, sulfamethoxazole

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Authors: Martin L. Zurita García, Erick O. Martínez Luque, Jessica Morales Perdomo, Yivy Martínez Duarte, Jorge Ari Noriega

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Colombia’s click beetles (Family Elateridae) are poorly documented in their diversity and taxonomy. There are listed 43 genera for Colombia but without a specific number of their species. No species of the genus Agriotes Eschscholtz (Elaterinae: Agriotini) have been recorded in Colombia. Currently, the subtribe Agriotina in the New World includes three genera: Agriotes, Bohartina Arias and Dalopius Eschscholtz. Historically, the genera Agriotes and Dalopius have had significant taxonomic problems due to their morphological resemblance. These similarities motivated several specialists to generate taxonomic movements such as synonyms and segregations of species in these genera on several occasions. To trying to solve these taxonomic problems, an author proposes some morphological characters present in the larvae, but mainly some genital characters of the females, such as the sclerotized plates of the bursa copulatrix. After examining material newly collected in Colombia, we found a click beetle having a unique combination of diagnostic characters that clearly separate it from any other genera of Agriotina. Hence, we describe and illustrate this click beetle under the name Raphaellus deusminutosi Zurita-García, Morales-Perdomo & Martínez-Luque n. gen. & n. sp., and we also compare this genus with the other New World genera of the subtribes Agriotina.

Keywords: click beetles, new genus, new species, elaterinae, raphaellus deusminutosi

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Authors: Abdul Hafeez, Samiya Shehzadi

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This research paper presents a different approach towards eco-friendly textile design by developing a sustainable composite fabric from orange peel for ladies' undergarments. The research focuses on utilizing orange peel to develop a unique orange leather/composite (fabric) through a process involving heating, extracting, and subsequent sun-drying to obtain the composite. The sustainable composite fabric shows properties that are favorable to the development of environmentally friendly undergarments, which not only offer UV protection but also possess healing properties for the skin. Through comprehensive testing and analysis, it has been determined that the orange peel composite fabric has zero harmful effects on the skin, making it a safe and desirable material for intimate wear. Furthermore, the research suggests that the orange peel composite fabric has the potential to reduce the rate of cancer cell growth. While the exact mechanisms and factors contributing to this effect require further investigation, the initial findings indicate promising aspects of the fabric in terms of potential cancer-preventive properties. Research contribution to the field of sustainable textile design by introducing a usual and eco-friendly approach utilizing orange peel waste. This work opens up avenues for further exploration and development of innovative materials that are both sustainable and beneficial for human health.

Keywords: sustainability, composite textiles, extracting, undergarments, eco-friendly, orange peels

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Authors: Karen L. Middlemiss, Denham G. Cook, Peter Jaksons, Alistair Jerrett, William Davison

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Lateralisation of cognitive function is a common phenomenon found throughout the animal kingdom. Strong biases in functional behaviours have evolved from asymmetrical brain hemispheres which differ in structure and/or cognitive function. In fish, lateralisation is involved in visually mediated behaviours such as schooling, predator avoidance, and foraging, and is considered to have a direct impact on species fitness. Currently, there is very little literature on the role of lateralisation in fish schools. The yellow-eyed mullet (Aldrichetta forsteri), is an estuarine and coastal species found commonly throughout temperate regions of Australia and New Zealand. This study sought to quantify visually mediated behaviours in yellow-eyed mullet to identify the significance of lateralisation, and the factors which influence functional behaviours in schooling fish. Our approach to study design was to conduct a series of tank based experiments investigating; a) individual and population level lateralisation, b) schooling behaviour, and d) optic lobe anatomy. Yellow-eyed mullet showed individual variation in direction and strength of lateralisation in juveniles, and trait specific spatial positioning within the school was evidenced in strongly lateralised fish. In combination with observed differences in schooling behaviour, the possibility of ontogenetic plasticity in both behavioural lateralisation and optic lobe morphology in adults is suggested. These findings highlight the need for research into the genetic and environmental factors (epigenetics) which drive functional behaviours such as schooling, feeding and aggression. Improved knowledge on collective behaviour could have significant benefits to captive rearing programmes through improved culture techniques and will add to the limited body of knowledge on the complex ecophysiological interactions present in our inshore fisheries.

Keywords: cerebral asymmetry, fisheries, schooling, visual bias

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Authors: Guanlin Wu, Jiajia Yao, Fang Liu, Junshuai Xue, Jincheng Zhang, Yue Hao

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Owing to the excellent thermal conductivity and ultra-wide bandgap, Aluminum nitride (AlN)/Gallium nitride (GaN) is a highly promising material to achieve high breakdown voltage and output power devices among III-nitrides. In this study, we explore the growth and characterization of polarization-induced AlN/GaN heterostructures using plasma-assisted molecular beam epitaxy (PA-MBE) on AlN-on-sapphire templates. To improve the crystal quality and demonstrate the effectiveness of the PA-MBE approach, a thick AlN buffer of 180 nm was first grown on the AlN-on sapphire template. This buffer acts as a back-barrier to enhance the breakdown characteristic and isolate leakage paths that exist in the interface between the AlN epilayer and the AlN template. A root-mean-square roughness of 0.2 nm over a scanned area of 2×2 µm2 was measured by atomic force microscopy (AFM), and the full-width at half-maximum of (002) and (102) planes on the X-ray rocking curve was 101 and 206 arcsec, respectively, using by high-resolution X-ray diffraction (HR-XRD). The electron mobility of 443 cm2/Vs with a carrier concentration of 2.50×1013 cm-2 at room temperature was achieved in the AlN/GaN heterostructures by using a polarization-induced GaN channel. The low depletion capacitance of 15 pF is resolved by the capacitance-voltage. These results indicate that the polarization-induced AlN/GaN heterostructures have great potential for next-generation high-temperature, high-frequency, and high-power electronics.

Keywords: AlN, GaN, MBE, heterostructures

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Authors: Kolja Them, Priyal Chikhaliwala, Sudeshna Chandra

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Purpose: The purpose of this work is to examine possibilities for noninvasive imaging and identification of tumor markers for cancer diagnosis. The proposed method uses antibody conjugated iron oxide nanoparticles and multicolor Magnetic Particle Imaging (mMPI). The method has the potential for radiation exposure free real-time estimation of local tumor marker concentrations in vivo. In this study, the method is applied to human Alpha-1-Fetoprotein. Materials and Methods: As tracer material AFP antibody-conjugated Dendrimer-Fe3O4 nanoparticles were used. The nanoparticle bioconjugates were then incubated with bovine serum albumin (BSA) to block any possible nonspecific binding sites. Parts of the resulting solution were then incubated with AFP antigen. MPI measurements were done using the preclinical MPI scanner (Bruker Biospin MRI GmbH) and the multicolor method was used for image reconstruction. Results: In multicolor MPI images the nanoparticles incubated only with BSA were clearly distinguished from nanoparticles incubated with BSA and AFP antigens. Conclusion: Tomographic imaging of human tumor marker Alpha-1-Fetoprotein is possible using AFP antibody conjugated iron oxide nanoparticles in presence of BSA. This opens interesting perspectives for cancer diagnosis.

Keywords: noninvasive imaging, tumor antigens, antibody conjugated iron oxide nanoparticles, multicolor magnetic particle imaging, cancer diagnosis

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Authors: Abdus-Samiᶜi Imam Arikewuyo

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Islam enjoins the spirit of cooperation among fellow mankind. This is particularly entrenched in the brotherhood phenomenon advocated by Islam. With cooperation, a group of people with diverse qualities and opportunities can facilitate a breakthrough in what is seemingly difficult, if not impossible. This understanding underscores the initiative of establishing multi-purpose cooperative societies for thrifts and savings among bonafide members, especially in developing nations. The spirit and objectives of the Multi-Purpose Cooperatives Societies gave birth to the founding of several of these organizations as a plausible economic outfit in Nigeria to provide succor to the socio-economic predicaments of members. Pertinently, many Islamic cooperative societies sprang up, carving a niche for themselves as Shariᶜah-based economic outfits to accommodate the yearnings of the Muslim populace. KWASU Al-Halal Cooperative Society, Malete, Nigeria, is one such organization that is not only Shariᶜah inclined but also institutional-based. This paper, therefore, aims to examine the operations and activities of this society with a view to determining its strength as a Shariᶜah-based economic outfit for the survival of its clients in a competitive multi-religious atmosphere. The study is both historical and descriptive; thus, it employed interview, observation, focus group discussion and hermeneutical methods as pertinent research tools. The research findings indicated that adopting the Shariᶜah prescriptions, KWASU Al-Halal Cooperative Society, as a representation of the Islamic cooperatives society, fulfilled the essence and goal of its establishment, serving as an outlet for meeting the socio-economic demands of its members regardless of religious inclinations. The paper recommended that stronger efforts should be made on proper record keeping, the conscientiousness of beneficiaries on loan refunds or payments on purchases and education of the loanees and guarantors.

Keywords: efficacy, Islamic cooperatives society, Kwasu al-halal cooperative society, shariᶜah

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Authors: M. M. Morgham, A. A. Hameda, N. A. Zriba, H. A. Jawan

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This paper aims to study the effect of cold work condition on the microstructure of Cu-1.5wt%Ti, and Cu-3.5wt%Ti and hence mechanical properties. The samples under investigation were machined and solution heat treated. X-ray diffraction technique is used to identify the different phases present after cold deformation by compression and also different heat treatment and also measuring the relative quantities of phases present. Metallographic examination is used to study the microstructure of the samples. The hardness measurements were used to indicate the change in mechanical properties. The results are compared with the mechanical properties obtained by previous workers. Experiments on cold compression followed by aging of Cu-Ti alloys have indicated that the most effective hardening of the material results from continuous precipitation of very fine particles within the matrix. These particles were reported to be β`-type, Cu4Ti phase. The β`-β transformation and particles coarsening within the matrix as well as a long grain boundaries were responsible for the averaging of Cu-1.5wt%Ti and Cu-3.5wt%Ti alloys. It is well know that plate like particles are β – type, Cu3Ti phase. Discontinuous precipitation was found to start at the grain boundaries and expand into grain interior. At the higher aging temperature a classic widmanstätten morphology forms giving rise to a coarse microstructure comprised of α and the equilibrium phase β. Those results were confirmed by X-ray analysis, which found that a few percent of Cu3Ti, β precipitates are formed during aging at high temperature for long time for both Cu- Ti alloys (i.e. Cu-1.5wt%Ti and Cu-3.5wt%Ti).

Keywords: metallographic, hardness, precipitation, aging

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Authors: Igbekoyi Olusola Esther, Olurankinse Felix

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This paper examined the factors that militate against Will writing among entrepreneurs in Ondo State Nigeria and the effect of intestate death on business continuity after the exit of the entrepreneurs. The paper was written with a view to providing information on the reasons why intestate death is common among entrepreneurs in Ondo State and the effects on continuity of business after death of the initial owners. Data were obtained from primary source through the administration of questionnaires to entrepreneurs drawn from 50 registered manufacturing companies. These companies have been in existence for a minimum of 10 years with minimum staff strength of 20 workers each. These companies were selected using the purposive random sampling technique in order to capture firms that meet the requirements of this paper. Data obtained were analyzed using descriptive statistics, chi-square and regression analysis. The findings of the paper revealed that administration of Will, traditional beliefs, Will execution procedures, age and non- admissibility of Wills in court are the major factors that militates against Will writing among entrepreneurs in Ondo State. It was also discovered that chaos and instability in business, reduction in sales and productivity, poor succession planning, polygamous nature of marriages, difficulty in sourcing for funds and gender preference are joint predictors of business continuity in event intestate death which is evident in the result where R2 =.954;(F 6, 26)= 89.644; (P < 0.01). The individual beta co-efficient, t- statistics and significance of each variable revealed that gender preference (.735; 7.031; .000) and poor succession plan (.402; 2.840; .009) have significant positive effect on business continuity; while reduction in sales and productivity (-.059; -.335; .740) and difficulty in sourcing for funds (-.217; -1.367; .188) have negative effect; other variables also have positive relationship but they are not significant. It is therefore concluded that business continuity after the exit of the entrepreneur is highly dependent on the rebuilding of confidence on Wills administration in ondo state Nigeria, proper succession planning and elimination of gender preferences.

Keywords: intestacy, business continuity, entrepreneurs, will, succession planning

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Authors: Sujata Sethi, Pawan Kumar, Sameer Aggarwal

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Depression and anxiety are of significant concern in youth with type 1 diabetes mellitus (T1DM) and these are correlated with glycemic control in multiple ways. The extent of depression and anxiety in children with T1DM remains poorly studied in India. The index study aimed to find the prevalence of depression and anxiety and their correlation with HbA1c (glycated hemoglobin) levels in children with T1DM. Material and methods: This study was a cross-sectional study carried out on a purposive sample of 45 children with T1DM. Depressive symptoms were assessed using Children’s Depression Rating Scale-Revised (CDRS-R) and anxiety symptoms were assessed using Spence Children’s Anxiety Scale (SCAS). Glycated hemoglobin (HbA1c) levels of all the participants were recorded. Results: 43 out of 45 children were analyzed as HbA1c status for two was not known. 48.8% were females. Mean age was 12.95+2.04. The average duration of diabetes was 3.63+1.82. Mean CDRS-R score was 41.6+12.25 and mean SCAS score was 33.07+12.29. Mean recording of HbA1c level was 7.90+1.51. 27 (62.8%) out of 43 participants had abnormal scores on CDRS-R and 24 (55.8%) out of 43 had abnormal scores on SCAS. The correlation coefficient between HbA1c levels and the CDRS-R score came out to be 0.57 and between HbA1c and SCAS, it was 0.53. Both correlations were significant with the p-value of < 0.02. Conclusion: Children with T1DM have high co-morbidity of depression and anxiety which is significantly correlated with the HbA1c levels. Thus, it becomes important to screen the patients for depression and anxiety for better outcomes.

Keywords: anxiety, depression, HbA1c, T1DM

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Authors: Morsli Mourad, Tahiri Mohamed, Samdi Azzeddine

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Casablanca is the biggest city in Morocco. It concentrates more than 60% of the economic and industrial activity of the kingdom. Its building and public works (BTP) sector is the leading source of inert waste scattered in open areas. This inert waste is a major challenge for the city of Casablanca, as it is not properly managed, thus causing a significant nuisance for the environment and the health of the population. Hence the vision of our project is to recycle and valorize concrete waste. In this work, we present concrete results in the exploitation of this abundant and permanent deposit. Typical wastes are concrete, clay and concrete bricks, ceramic tiles, marble panels, gypsum, scrap metal, wood . The work performed included: geolocation with a combination of artificial intelligence and Google Earth, estimation of the amount of waste per site, sorting, crushing, grinding, and physicochemical characterization of the samples. Then, we proceeded to the exploitation of the types of substrates to be developed: light cement, coating, and glue for ceramics... The said products were tested and characterized by X-ray fluorescence, specific surface, resistance to bending and crushing, etc. We will present in detail the main results of our research work and also describe the specific properties of each material developed.

Keywords: déchets de démolition et des chantiers de construction, logiciels de combinaison SIG, valorisation de déchets inertes, enduits, ciment leger, casablanca

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Authors: Valeria Corinaldesi, Nicola Generosi, Jacopo Donnini

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Ultra high performance concrete (UHPC) is an innovative material which tends to exhibit superior properties such as incredible mechanical and durability performance and non-brittleness behavior. Over the last twenty years, phenomenal advances have taken place in the research and application of UHPC. Recently, the approach is to improve UHPC sustainability by reducing its embodied energy. First of all, this goal can be achieved by reducing Portland cement dosage. In this work, an experimental investigation was carried out to characterize the mechanical behavior and durability of UHPCs prepared by reducing the cement amount by 30% in order to verify the impact of lower cement content and higher water-to-cement ratio on both mechanical performance and durability, if any. Eight different UHPC mixtures were compared, with two different cement dosages (either 1000 or 700 kg) and four different brass-coated steel fibres dosages (0 - 50 - 100 - 150 kg), in terms of 28-day compressive and flexural strengths. Then, the mixtures prepared with the lower cement content were further investigated in terms of abrasion resistance, water absorption, freezing and thawing cycles, and resistance to sulphate attack. Results obtained showed the feasibility of reducing cement dosage without compromising mechanical performance and UHPC's extraordinary durability.

Keywords: abrasion resistance, durability, eco-efficiency, freeze-thawing cycles, steel fibres, sulphate exposure, sustainability, UHPC

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Authors: Anastasia Stamatiou, Melissa Obermeyer, Ludger J. Fischer, Philipp Schuetz, Jörg Worlitschek

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This study evaluates unbranched, saturated carboxylic esters with respect to their suitability to be used as storage media for latent heat storage applications. Important thermophysical properties are gathered both by means of literature research as well as by experimental measurements. Additionally, esters are critically evaluated against other common phase-change materials in terms of their environmental impact and their economic potential. The experimental investigations are performed for eleven selected ester samples with a focus on the determination of their melting temperature and their enthalpy of fusion using differential scanning calorimetry. Transient Hot Bridge was used to determine the thermal conductivity of the liquid samples while thermogravimetric analysis was employed for the evaluation of the 5% weight loss temperature as well as of the decomposition temperature of the non-volatile samples. Both experimental results and literature data reveal the high potential of esters as phase-change materials. Their good thermal and environmental properties as well as the possibility for production from natural sources (e.g. vegetable oils) render esters as very promising for future storage applications. A particularly high short term application potential of esters could lie in low temperature storage applications where the main alternative is using salt hydrates as phase-change material.

Keywords: esters, phase-change materials, thermal properties, latent heat storage

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Authors: Alparslan A. Balta, Hilmi Yurdakul, Orkun Tunckan, Servet Turan, Arife Yurdakul

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A silicon oxynitride (Si2N2O), the mineralogical name is “Sinoite”, reveals the outstanding physical, mechanical and thermal properties, e.g., good oxidation resistance at high temperatures, high fracture toughness with rod shape, high hardness, low theoretical density, good thermal shock resistance by low thermal expansion coefficient and high thermal conductivity. In addition, the orthorhombic crystal structure of Si2N2O allows accommodating the rare earth (RE) element atoms along the “c” axis due to existing large structural interstitial sites. Here, 0.02 to 0.12 wt. % Nd3+ doped Si2N2O samples were successfully synthesized by spark plasma sintering (SPS) method at 30MPa pressure and 1650oC temperature. Li2O was also utilized as a sintering additive to take advantage of low eutectic point during synthesizing. The specimens were characterized in detail by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and cathodoluminescence (CL) in SEM and photoluminescence (PL) spectroscopy. Based on the overall results, the Si2N2O phase was obtained above 90% by the SPS route. Furthermore, Nd3+: Si2N2O samples showed a very broad intense emission peak between 400-700 nm, which corresponds to white color. Therefore, this material can be considered as a promising candidate for white light-emitting diodes (WLEDs) purposes. This study was supported by TUBITAK under project number 217M667.

Keywords: neodymium, oxynitride, Si₂N₂O, WLEDs

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Authors: Freitas Vania Moreira, Rodrigues B. B., Araujo M.B., Silva D. R., Sousa A. C., Araujo K. P., Pimentel R. R., Cares J. E., Junqueira N. T. V.

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The Pitahayas are cactus native from America and abundant in arid regions. The cultivation is based mainly on the following species: Hylocereus undatus, H. polyrhizus, H. setaceus and H. megalanthus, being H. undatus the most cultivated in Brazil. The pitahaya cultivation is recent in Brazil and is concentrated in São Paulo. Meloidogyne enterolobii is of unknown origin being distributed in several countries. This nematode has recently been detected in Brazil causing damage in several crops. Similarly, M. incognita is a widely distributed pathogen in Brazil. The objective of this study is to evaluate the following accesses of pitahaya to M. enterolobii: CPAC- Py H. hundatus 01, 02, 03, 04, 05, 06, 07 and 08; CPAC - Py H. costaricense 8A; CPAC - Py Selenicereus setaceus 17 and CPAC - Py S. megalantus 22. And the following accesses to M. incognita: CPAC- Py H. hundatus 05; CPAC - Py H. costaricense 8A; CPAC - Py S. setaceus 17 and CPAC - Py S. megalantus 22. According to the results, CPAC – Py H. hundatus 01, 02, 03, 04 and 07 were considered resistant. While CPAC - Py 05 and 08 was susceptible. CPAC-Py 06 also was considered susceptible, because there was the reaction of susceptibility in one of the trials. Given this wide diversity in H. hundatus and being this species the most cultivated in Brazil it is suggested to work more with this material in Embrapa Cerrados. CPAC - Py H. costaricense 8A behaved as susceptible in one of the trials. CPAC - Py S. setaceus 17 and CPAC – Py S. megalantus 22 were considered highly susceptible. The susceptibility of S. megalantus is widely described in the literature. In relation to M. incognita, there were differences between the results in both experiments, but all behaved as susceptible in at least one of the tests.

Keywords: pitaya, meloidogyne, fruit, resistance

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Authors: Andrey V. Malyshev, Anna B. Petrova, Anatoly P. Surzhikov

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The article presents the results of the influence of diamagnetic additives on the defects level of ferrite ceramics. For this purpose, we use a previously developed method based on the mathematical analysis of experimental temperature dependences of the initial permeability. A phenomenological expression for the description of such dependence was suggested and an interpretation of its main parameters was given. It was shown, that the main criterion of the integral defects level of ferrite ceramics is the relation of two parameters correlating with elastic stress value in a material. Model samples containing a controlled number of intergranular phase inclusions served to prove the validity of the proposed method, as well as to assess its sensitivity in comparison with the traditional XRD (X-ray diffraction) analysis. The broadening data of diffraction reflexes of model samples have served for such comparison. The defects level data obtained by the proposed method are in good agreement with the X-ray data. The method showed high sensitivity. Therefore, the legitimacy of the selection relationship β/α parameters of phenomenological expression as a characteristic of the elastic state of the ferrite ceramics confirmed. In addition, the obtained data can be used in the detection of non-magnetic phases and testing the optimal sintering production technology of soft magnetic ferrites.

Keywords: cure point, initial permeability, integral defects level, homogeneity

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Authors: W. Mughees, M. Alahmad

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Water is the most significant entity that controls local and global development. For the Gulf region, especially Saudi Arabia, with its limited potable water resources, the potential of the fresh water problem is highly considerable. In this research, the study involves the design and analysis of pinch-based water/wastewater networks. Multiple water/wastewater networks were developed using pinch analysis involving direct recycle/material recycle method. Property-integration technique was adopted to carry out direct recycle method. Particularly, a petroleum refinery was considered as a case study. In direct recycle methodology, minimum water discharge and minimum fresh water resource targets were estimated. Re-design (or retrofitting) of water allocation in the networks was undertaken. Chemical Oxygen Demand (COD) and hardness properties were taken as pollutants. This research was based on single and double contaminant approach for COD and hardness and the amount of fresh water was reduced from 340.0 m3/h to 149.0 m3/h (43.8%), 208.0 m3/h (61.18%) respectively. While regarding double contaminant approach, reduction in fresh water demand was 132.0 m3/h (38.8%). The required analysis was also carried out using mathematical programming technique. Operating software such as LINGO was used for these studies which have verified the graphical method results in a valuable and accurate way. Among the multiple water networks, the one possible water allocation network was developed based on mass exchange.

Keywords: minimization, water pinch, water management, pollution prevention

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Authors: Daneal Rorke, Gueguim Kana

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The shift towards renewable energy sources for biofuel production has received increasing attention. However, the use and pre-treatment of lignocellulosic material are inundated with the generation of fermentation inhibitors which severely impact the feasibility of bioprocesses. This study reports the profiling of all volatile compounds generated during microwave assisted chemical pre-treatment of sorghum leaves. Furthermore, the optimization of reducing sugar (RS) from microwave assisted acid pre-treatment of sorghum leaves was assessed and gave a coefficient of determination (R2) of 0.76, producing an optimal RS yield of 2.74 g FS/g substrate. The development of an intelligent model to predict volatile compound fractions gave R2 values of up to 0.93 for 21 volatile compounds. Sensitivity analysis revealed that furfural and phenol exhibited high sensitivity to acid concentration, alkali concentration and S:L ratio, while phenol showed high sensitivity to microwave duration and intensity as well. These findings illustrate the potential of using an intelligent model to predict the volatile compound fraction profile of compounds generated during pre-treatment of sorghum leaves in order to establish a more robust and efficient pre-treatment regime for biofuel production.

Keywords: artificial neural networks, fermentation inhibitors, lignocellulosic pre-treatment, sorghum leaves

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Authors: Oyuna Weina

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This study examines how musicians use visual and zoological metaphors for singing technique and voice quality in a genre of traditional music called urtiin duu (‘long song’) in Alshaa, Inner Mongolia, China. Previous studies have discussed melodic contour in Mongol music, but little study of the intersection of singing technique, visual and zoological metaphors has yet been undertaken. The purpose of this study is to address this lack by analysing urtiin duu itself, traditional pedagogy and performances, all of which have been inspired and are assessed by reference to nature and mobile pastoral herding practices. This study investigates the visual and zoological metaphors related to urtiin duu especially colour, the shape of the circle and animals in the Mongol community. Urtiin duu singing is associated with certain colours in song texts, in selection of repertoire and in the status of singers. Musicians also use colour to describe timbre. These colours in turn reference worship of nature, religions, and daily practices of most Mongols in Alshaa. Moreover, voice quality and singing technique are often related to the animals not only in song text but also in the approach to breathing and to melodic contour. Additionally, the concept of boronhoi (‘the shape of circle’), not only is applied to the melodic contour but also to the voice quality and singing technique. These three factors illustrate the connections among nature, spiritual world and everyday herding life of Mongols. These different connections provide evidence of multi-layered meanings. In contemporary Alshaa, urtiin duu singers received Western musical training from the city and returned to their homelands to perform urtiin duu. In doing so, they are also trying to reconnect with the history, nature and spiritual world in order to achieve their ideal sound. Within a multicultural society, singers negotiate amongst themselves, and with ethnic groups, audiences and government officials. The power of the metaphor therefore assists and reconnects the strength of regional identity and ethnic identity in Alshaa.

Keywords: Alshaa, urtiin duu, visual, zoological metaphors

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Authors: M. Błoch, P. Karpiński, P. Gasperowicz, R. Płoski, A. Lebioda, P. Skiba, A. Rozensztrauch, D. Patkowski, R. Śmigiel

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Introduction: The cause of the isolated form of esophageal atresia has been yet unknown. Objectives: The primary objective of this study was to indicate epigenetic factors which may play an important role in the etiopathogenesis of esophageal atresia. Methods: We recruited a group of 6 pairs of twins, among whom one of the twins developed EA. The selection of such a group for testing allows for excluding external factors (e.g., infections, drugs, toxins) as the cause of the birth defect. The analyzes were performed with the use of genetic material isolated from the whole blood and esophagus tissue of a patient with EA. The reduced representation bisulphite sequencing (RRBS) technique was used to study the change in the genomic imprinting -a change in the expression of genes, which may be the epigenetic cause of EA. Results: In the course of the analyzes, significant hypomethylation and hypermethylation regions were identified. 65 genes with probably increased expression and 65 with decreased expression were selected. These genes have not been marked in literature as possibly pathogenic in esophageal atresia. However, their participation in the pathogenesis of esophageal atresia cannot be clearly excluded. Conclusion: We suggest a role of hypomethylation or hypermethylation of selected genes as one of the possible epigenetic factors in EA pathogenesis. The use of the RRBS technique in the search for the cause of EA is pioneer research; therefore, it seems necessary to extend the research group to new patients with EA. Acknowledgment: The work was supported by the National Science Centre, Poland, under research project 2016/21/N/NZ5/01927.

Keywords: esophageal atresia, epigenetics, embryonic development, surgery, genes expression, twins

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Authors: Andreia Cucuruz, Cristina Daniela Ghitulica, Georgeta Voicu, Cristina Busuioc

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Ceramics based on calcium phosphates have lately increased attention for tissue engineering because they can be used as substitute bones or for bone regeneration since they mimic very well the nanostructure of tough bone tissue, but also because of other advantages such as a very good biocompatibility and osseointegration. This study aims the preparation and characterization of ceramic materials on the basis of TCP (Ca₃(PO₄)₂), within which calcium ions are substituted by magnesium ions (Mg²⁺) in order to improve the regenerative properties of these materials. TCP-Mg material was synthesized by chemical precipitation method using calcium oxide (CaO) and phosphoric acid (H₃PO₄) as precursors. The objective was to obtain powders with different concentrations of Mg in order to analyze the effect of magnesium ions on the physicochemical properties of phosphate ceramics and in vitro degradation in simulated biological fluid (SBF). Ceramic powders were characterized in vitro but also from the compositional and microstructural point of view. TCP_Mg powders were prepared through wet chemical method from calcium oxide (CaO), magnesium oxide nanopowder (MgO < 50 nm particle size (BET) Sigma Aldrich), phosphoric acid (H₃PO₄ - 85 wt.% in H₂O, 99.99% trace metals basis - Sigma Aldrich). In order to determine the quantities of raw materials, calculations were performed to obtain HAp with Ca/P ratio of 1.5.

Keywords: bone regeneration, magnesium substitution, tricalcium phosphate, tissue engineering

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Authors: L. Khalfa, M. Bagane, M. L. Cervera, S. Najjar

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The aim of this work is to present a low cost adsorbent for removing toxic heavy metals from aqueous solutions. Therefore, we are interested to investigate the efficiency of natural clay minerals collected from south Tunisia and their modified form using sulfuric acid in the removal of toxic metal ions: Zn(II) and Pb(II) from synthetic waste water solutions. The obtained results indicate that metal uptake is pH-dependent and maximum removal was detected to occur at pH 6. Adsorption equilibrium is very rapid and it was achieved after 90 min for both metal ions studied. The kinetics results show that the pseudo-second-order model describes the adsorption and the intraparticle diffusion models are the limiting step. The treatment of natural clay with sulfuric acid creates more active sites and increases the surface area, so it showed an increase of the adsorbed quantities of lead and zinc in single and binary systems. The competitive adsorption study showed that the uptake of lead was inhibited in the presence of 10 mg/L of zinc. An antagonistic binary adsorption mechanism was observed. These results revealed that clay is an effective natural material for removing lead and zinc in single and binary systems from aqueous solution.

Keywords: heavy metal, activated clay, kinetic study, competitive adsorption, modeling

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Authors: Jakub Bartus, Jaroslav Odrobinak

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In general, composite steel and concrete structures present an effective structural solution utilizing the full potential of both materials. As they have numerous advantages on the construction side, they can greatly reduce the overall cost of construction, which has been the main objective of the last decade, highlighted by the current economic and social crisis. The study represents not only an analysis of composite beams’ behavior having web openings but emphasizes the influence of these openings on the total strain distribution at the level of the steel bottom flange as well. The major investigation was focused on a change in structural performance with respect to various layouts of openings. Examining this structural modification, an improvement of load carrying capacity of composite beams was a prime objective. The study is divided into analytical and numerical parts. The analytical part served as an initial step into the design process of composite beam samples, in which optimal dimensions and specific levels of utilization in individual stress states were taken into account. The numerical part covered the discretization of the preset structural issue in the form of a finite element (FE) model using beam and shell elements accounting for material non–linearities. As an outcome, several conclusions were drawn describing and explaining the effect of web opening presence on the structural performance of composite beams.

Keywords: beam, steel flange, total strain, web opening

Procedia PDF Downloads 58

Authors: Bernett Nkwayi Mulungo

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There are vast community music projects in South African townships, and their courses range from music theory aural practical individual and ensemble lessons on orchestral instruments and recorders – these instruments being primarily “Western”. Despite this relative success – indeed one of the few in the realm of arts in post-apartheid South Africa – what remains troubling is the dominance of western thought (as music theory) and modes of teaching music that maintain the idea of music study as alien in black communities. This identified problem speaks to a significant theme, namely: Arts education for community development, which is my area of interest. Primarily for, it is a timely platform to firmly entrench appreciation, understanding, and, most undoubtedly, the value(s) of the arts to the youth. Drawing on one’s experience as a lecturer in (and graduate from) a South African tertiary institution and as a teacher in a community project, this research will interrogate the content of some of the program(s): from the theoretical material taught in music theory classes to the practical repertoire taught and/or performed. The focal point of this research is on how this content informs or speaks to its intended “beneficiaries” – the African youth. Through these and other considerations, the paper aims to sketch the potentially radical consequences that transformed music education at community and earlier levels will have for higher education music studies in South Africa.

Keywords: decolonization, Africanization, indigenous knowledge, community engagement

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Authors: Mohd Kamil Vakil

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Air Pollution is caused by the introduction of chemicals in the biosphere. Primary pollutants on reaction with the components of the earth produce Secondary Pollutants like Smog. Ozone is the main ingredient of Smog. The ground level ozone is created by the chemical reactions between Nitrogen Oxides (NOx) and Volatile Organic Compounds (VOCs) in the presence of Sunlight. This ozone can enter inside and call as indoor ozone. The automobile emissions in both moving and idling conditions contribute to the indoor ozone formation. During engine ignition and shutdown, motor vehicles emit the ozone forming pollutants like NOx and VOCs, and the phenomena are called Cold Start and Hot-Soak respectively. Subjects like Chronic Obstructive Pulmonary Disease (COPD) and asthma associated with chronic respiratory diseases are susceptible to the harmful effects of Indoor Ozone. The most common cause of COPD other than smoking is the long-term contract with harmful pollutants like ground-level ozone. It is estimated by WHO that COPD will become the third leading cause of all deaths worldwide by 2030. In this paper, the cold-start and hot-soak vehicle emissions are studied in the context of accumulation of oxides of nitrogen at the outer walls of the building which may cause COPD. The titanium oxide coated building material is further discussed as an absorber of NOx when applied to the walls and roof.

Keywords: indoor air quality, cold start emission, hot-soak, ozone

Procedia PDF Downloads 187

Authors: Nguyen-Tri Phuong, Triki Ennouri, Gauvin Chantal, Tuduri Ludovic, Vu-Khanh Toan

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Hand injuries due to mechanical hazards such as cuts and punctures are major risks and concerns for several occupational groups, particularly for workers in the metal manufacturing sector and mechanical automotive services. Personal protective equipment such as gloves or clothing is necessary for many professionals to protect against a variety of occupational hazards, which arise daily in their work environments. In many working places such as metal manufacturing or automotive services, mechanical hazards often occur together with industrial contaminants, particularly metalworking fluids (MWFs). The presence of these contaminants could modify the properties of gloves made from polymeric materials and thus increase the risk of hand injuries for workers. The focus of this study is to determine the swelling characteristics and the resistance of six polymer membranes when they are contaminated with several industrial metalworking fluids. These polymer membranes, commonly used in protective gloves, are nitrile, neoprene, vinyl, butyl, polyurethane and latex rubbers. Changes swelling index were continuously followed during the contamination procedure to compare the performance of each polymer under different conditions. The modification of the samples surface, tensile properties during the contamination process was also investigated. The effect of temperature on mechanical properties and morphology of material was also examined.

Keywords: metalworking fluid, swelling behavior, protective glove materials, elastomers

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Authors: Soroush Momeni

Abstract:

Excellent damping capacity and superelasticity of the bulk NiTi shape memory alloy (SMA) makes it a suitable material of choice for tools in machining process as well as tribological systems. Although thin film of NiTi SMA has a same damping capacity as NiTi bulk alloys, it has a poor mechanical properties and undesirable tribological performance. This study aims at eliminating these application limitations for NiTi SMA thin films. In order to achieve this goal, NiTi thin films were magnetron sputtered as an interlayer between reactively sputtered hard TiCN coatings and hard work tool steel substrates. The microstructure, composition, crystallographic phases, mechanical and tribological properties of the deposited thin films were analyzed by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), nanoindentation, ball–on-disc, scratch test, and three dimensional (3D) optical microscopy. It was found that under a specific coating architecture, the superelasticity of NiTi inter-layer can be combined with high hardness and wear resistance of TiCN protective layers. The obtained results revealed that the thickness of NiTi interlayers is an important factor controlling mechanical and tribological performance of bi-layer composite coating systems.

Keywords: PVD coatings, sliding wear, hardness, tool steel

Procedia PDF Downloads 269